<template>
  <div>
    <el-select popper-class="virtualselect"
      class="virtual-select-custom-style"
      :value="defaultValue"
      filterable
      remote
      :remote-method="filterMethod"
      default-first-option
      clearable
      :placeholder="placeholder"
      :disabled="disabled"
      :multiple="isMultiple"
      :allow-create="allowCreate"
      @visible-change="visibleChange"
      v-on="$listeners"
      :no-data-text="$t('noResult')"
      @clear="clearChange">
      <virtual-list ref="virtualList"
        class="virtualselect-list"
        :data-key="value"
        :data-sources="selectArr"
        :data-component="itemComponent"
        :keeps="keepsParams"
        :extra-props="{
          label: label,
          value: value,
          isRight: isRight,
          isConcat: isConcat,
          concatSymbol: concatSymbol,
          concatKey: concatKey
        }"></virtual-list>
    </el-select>
  </div>
</template>
<script>
import { mapState } from 'vuex'
import virtualList from 'vue-virtual-scroll-list'
import ElOptionNode from '~/components/ElOptionNode.vue'
const validatenull = (val) => {
  if (typeof val === 'boolean') {
    return false
  }
  if (typeof val === 'number') {
    return false
  }
  if (val instanceof Array) {
    if (val.length === 0) return true
  } else if (val instanceof Object) {
    if (JSON.stringify(val) === '{}') return true
  } else {
    if (
      val === 'null' ||
      val === null ||
      val === 'undefined' ||
      val === undefined ||
      val === ''
    )
      return true
    return false
  }
  return false
}
export default {
  name: 'VirtualSelect',
  components: {
    'virtual-list': virtualList,
  },
  model: {
    prop: 'bindValue',
    event: 'change',
  },
  props: {
    // 数组
    list: {
      type: Array,
      default() {
        return []
      },
    },
    // 显示名称
    label: {
      type: String,
      default: '',
    },
    // 标识
    value: {
      type: String,
      default: '',
    },
    // 是否拼接label | value
    isConcat: {
      type: Boolean,
      default: false,
    },
    // 拼接label、value符号
    concatSymbol: {
      type: String,
      default: ' | ',
    },
    // 拼接的字段
    concatKey: {
      type: String || null,
      default: null,
    },
    // 显示右边
    isRight: {
      type: Boolean,
      default: false,
    },
    // 加载条数
    keepsParams: {
      type: Number,
      default: 10,
    },
    // 绑定的默认值
    bindValue: {
      type: [String, Array],
      default() {
        if (typeof this.bindValue === 'string') return ''
        return []
      },
    },
    // 是否多选
    isMultiple: {
      type: Boolean,
      default: false,
    },
    // 输入框占位文本
    placeholder: {
      type: String,
      default: '请选择',
    },
    // 是否禁用
    disabled: {
      type: Boolean,
      default: false,
    },
    // 是否允许创建条目
    allowCreate: {
      type: Boolean,
      default: false,
    },
  },
  data() {
    return {
      itemComponent: ElOptionNode,
      selectArr: [],
      defaultValue: null, // 绑定的默认值
    }
  },
  computed: {
    ...mapState({
      toolify_isLogin: (state) => state.toolify_isLogin,
    }),
  },
  watch: {
    list() {
      this.init()
    },
    bindValue: {
      handler(val, oldVal) {
        this.defaultValue = this.bindValue
        if (validatenull(val)) this.clearChange()
        this.init()
      },
      immediate: false,
      deep: true,
    },
  },
  mounted() {
    this.defaultValue = this.bindValue
    this.init()
  },
  methods: {
    init() {
      if (!this.defaultValue || this.defaultValue?.length === 0) {
        //this.selectArr = this.list
        this.selectArr = []
      } else {
        // 回显问题
        // 由于只渲染固定keepsParams（10）条数据,当默认数据处于10条之外,在回显的时候会显示异常
        // 解决方法:遍历所有数据,将对应回显的那一条数据放在第一条
        this.selectArr = []
        let obj = {}
        if (typeof this.defaultValue === 'string' && !this.isMultiple) {
          if (this.allowCreate) {
            const arr = this.selectArr.filter((val) => {
              return val[this.value] === this.defaultValue
            })
            if (arr.length === 0) {
              const item = {}
              // item[this.value] = `Create-${this.defaultValue}`
              item[this.value] = this.defaultValue
              item[this.label] = this.defaultValue
              item.allowCreate = true
              this.selectArr.push(item)
              this.$emit('selChange', item)
            } else {
              this.$emit('selChange', arr[0])
            }
          }

          // 单选
          for (let i = 0; i < this.selectArr.length; i++) {
            const element = this.selectArr[i]
            if (
              element[this.value]?.toLowerCase() ===
              this.defaultValue?.toLowerCase()
            ) {
              obj = element
              this.selectArr?.splice(i, 1)
              break
            }
          }
          this.selectArr?.unshift(obj)
        } else if (this.isMultiple) {
          if (this.allowCreate) {
            this.defaultValue.map((v) => {
              const arr = this.selectArr.filter((val) => {
                return val[this.value] === v
              })
              if (arr?.length === 0) {
                const item = {}
                // item[this.value] = `Create-${v}`
                item[this.value] = v
                item[this.label] = v
                item.allowCreate = true
                this.selectArr.push(item)
                this.$emit('selChange', item)
              } else {
                this.$emit('selChange', arr[0])
              }
            })
          }

          // 多选
          for (let i = 0; i < this.selectArr.length; i++) {
            const element = this.selectArr[i]
            this.defaultValue?.map((val) => {
              if (element[this.value]?.toLowerCase() === val?.toLowerCase()) {
                obj = element
                this.selectArr?.splice(i, 1)
                this.selectArr?.unshift(obj)
              }
            })
          }
        }
      }
    },
    // 搜索
    filterMethod(query) {
      if (!validatenull(query?.trim())) {
        this.$refs.virtualList.scrollToIndex(0) // 滚动到顶部
        let timer = setTimeout(() => {
          this.selectArr = this.list.filter((item) => {
            return this.isRight || this.isConcat
              ? item[this.label]
                  .trim()
                  ?.toLowerCase()
                  ?.indexOf(query?.trim()?.toLowerCase()) > -1 ||
                  (this.concatKey &&
                    item[this.concatKey]
                      .trim()
                      ?.toLowerCase()
                      ?.indexOf(query?.trim()?.toLowerCase()) > -1)
              : /* ||
                  item[this.value]
                    ?.toLowerCase()
                    ?.indexOf(query?.trim()?.toLowerCase()) > -1 */
                item[this.label]
                  ?.toLowerCase()
                  ?.indexOf(query?.trim()?.toLowerCase()) > -1
          })

          this.$nextTick(() => {
            clearTimeout(timer)
          })
        }, 100)
      } else {
        let timer = setTimeout(() => {
          this.init()

          this.$nextTick(() => {
            clearTimeout(timer)
          })
        }, 100)
      }
    },
    visibleChange(bool) {
      if (!bool) {
        this.$refs.virtualList.reset()
        this.init()
      }
      this.$emit('visible-change', bool)
    },
    clearChange() {
      if (typeof this.defaultValue === 'string') {
        this.defaultValue = ''
      } else if (this.isMultiple) {
        this.defaultValue = []
      }
      this.visibleChange(false)
    },
  },
  beforeDestroy() {
    this.selectArr = []
  },
}
</script>
<style scoped>
/* .virtual-select-custom-style ::v-deep .el-select-dropdown__item {
  // 设置最大宽度，超出省略号，鼠标悬浮显示
  // options 需写 :title="source[label]"
  width: 250px;
  display: inline-block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
} */
.virtualselect {
  max-height: 245px;
  overflow-y: auto;
  /* // 设置最大高度
  &-list {
    max-height:245px;
    overflow-y:auto;
  } */
}
.virtualselect-list {
  max-height: 245px;
  overflow-y: auto;
}
.el-select {
  width: 100%;
}
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
  background-color: transparent;
  cursor: pointer;
  margin-right: 5px;
}
::-webkit-scrollbar-thumb {
  background-color: rgba(144, 147, 153, 0.3) !important;
  border-radius: 3px !important;
}
::-webkit-scrollbar-thumb:hover {
  background-color: rgba(144, 147, 153, 0.5) !important;
}
::-webkit-scrollbar-track {
  background-color: transparent !important;
  border-radius: 3px !important;
  -webkit-box-shadow: none !important;
}
::v-deep .el-select__tags {
  flex-wrap: unset;
  overflow: auto;
}
</style>
<style lang="scss">
.virtualselect {
  max-width: 576px;
  .el-select-dropdown__item {
    display: block;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
  }
}

.virtual-select-custom-style {
  .el-icon-circle-check {
    font-size: 18px;
    &:before {
      content: '\e6da';
    }
  }
}
</style>

